Speaking from an undisclosed location earlier on Tuesday, Mr Mnangagwa said he had fled abroad two weeks ago when he learned of a plot to kill him.

A city sings

Fergal Keane, BBC Africa editor, Harare

Driving through Harare, the cheers and the blaring of car horns signalled the end of the Mugabe era.

The man who dominated Zimbabwe for so long has already begun to fade into history here. It is a city singing with the noise of joy.

Exactly a week after the military first moved against President Mugabe, I was standing in parliament as legislators debated the motion to impeach him.

Suddenly, there was cheering.

An usher approached the speaker and handed him a letter. He stood to speak and we strained to hear his words. They were muffled but momentous. Robert Mugabe had resigned.

On the floor of the parliament I met jubilant MPs. Some danced. Celebrations spilled into the hallways and out into the street.

A people who endured white minority rule and then saw their independence become tyranny found themselves suddenly free.

'Let him rest in his last days'

UK Prime Minister Theresa May said Mr Mugabe's resignation "provides Zimbabwe with an opportunity to forge a new path free of the oppression that characterised his rule".

She said that former colonial power Britain, "as Zimbabwe's oldest friend", will do all it can to support free and fair elections and the rebuilding of the Zimbabwean economy.

Opposition leader Morgan Tsvangirai told the BBC he hoped that Zimbabwe was on a "new trajectory" that would include free and fair elections. He said Mr Mugabe should be allowed to "go and rest for his last days".

In other reaction:

The US Embassy in Harare, the capital, said it was a "historic moment" and congratulated Zimbabweans who "raised their voices and stated peacefully and clearly that the time for change was overdue"

South Africa's main opposition Democratic Alliance welcomed the move, saying Mr Mugabe had turned from "liberator to dictator"

Prominent Zimbabwean opposition politician David Coltart tweeted: "We have removed a tyrant but not yet a tyranny"

Civil society group the Platform for Concerned Citizens called for dialogue between all political parties, which it said should lead to the formation of a national transitional authority

Robert Mugabe won elections during his 37 years in power, but over the past 15 years these were marred by violence against political opponents.

He presided over a deepening economic crisis in Zimbabwe, where people are on average 15% poorer now than they were in 1980.

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Media captionActivist and political candidate Vimbaishe Musvaburi breaks down in tears of joy

However, Mr Mugabe was not forced out after decades in power by a popular mass movement but rather as a result of political splits within his Zanu-PF party.

The leader of the influential liberation war veterans - former allies of Mr Mugabe - said after the army takeover that Mr Mugabe was a "dictator", who "as he became old, surrendered his court to a gang of thieves around his wife".